Pre-formed polymer matrix disc to maintain uniform cell spacing

ABSTRACT

An emissive display system includes an electro-optic device having a first substantially transparent substrate including a first electrically conductive material associated therewith. A second substantially transparent substrate is spaced apart from the first substrate to define a cavity and includes a second electrically conductive material associated therewith. One or more spacing members are positioned within the cavity and include one or more polymer matrix discs configured to maintain a cell spacing between the first and second substrates. An electro-optic medium is disposed within the cavity and is variably transmissive such that the electro-optic device is operable between substantially clear and darkened states, and includes at least one solvent, at least one anodic material, and at least one cathodic material. A substantially transparent light emitting display is operably coupled to the electro-optic device, which is in the darkened state when the light emitting display is emitting light.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ProvisionalPatent Application No. 61/881,941, filed on Sep. 24, 2013, entitled“ELECTRO-OPTIC DEVICE,” the entire disclosure of which is herebyincorporated herein by reference.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to an emissive display system,and more particularly, an emissive display system having anelectro-optic device providing a selectively active background for asubstantially transparent light emitting display.

BACKGROUND OF THE DISCLOSURE

Electro-optic assemblies are being used in various vehicular andbuilding applications, e.g., within rearview display devices andvariably transmissive windows. Use of these assemblies in variousapplications can be limited by cost, aesthetic and functionalconsiderations. Accordingly, new electro-optic assembly designs,configurations and assemblies, along with methods of making them, areneeded particularly in view of reducing material and processing costs,improving aesthetics and/or enhancing functionality.

SUMMARY OF THE PRESENT DISCLOSURE

According to one aspect of the present disclosure, an emissive displaysystem includes an electro-optic device having a first substantiallytransparent substrate including a first electrically conductive materialassociated therewith. A second substantially transparent substrate isspaced apart from the first substrate to define a cavity and includes asecond electrically conductive material associated therewith. One ormore spacing members are positioned within the cavity. The one or morespacing members include one or more polymer matrix discs configured tomaintain a cell spacing between the first and second substrates. Anelectro-optic medium is disposed within the cavity. The electro-opticmedium is variably transmissive such that the electro-optic device isoperable between substantially clear and darkened states. Theelectro-optic medium includes at least one solvent, at least one anodicmaterial, and at least one cathodic material. A substantiallytransparent light emitting display is operably coupled to theelectro-optic device. The electro-optic device is in the darkened statewhen the light emitting display is emitting light.

According to another aspect of the present disclosure, an emissivedisplay system includes an electro-optic device having a firstsubstantially transparent substrate including a first electricallyconductive material associated therewith. A second substantiallytransparent substrate is spaced apart from the first substrate to definea cavity and includes a second electrically conductive materialassociated therewith. One or more spacing members are positioned withinthe cavity. The one or more spacing members are configured to maintain acell spacing between the first and second substrates. An electro-opticmedium is disposed within the cavity and variably transmissive such thatthe electro-optic device is operable between a substantially clear stateand a darkened state. A substantially transparent light emitting displayis operably coupled to the electro-optic device and is configured todisplay a visible image by selectively emitting light. The electro-opticdevice is in the darkened state when the light emitting display isemitting light.

According to yet another aspect of the present disclosure, an emissivedisplay system includes an electro-optic device having a firstsubstantially transparent substrate including a first electricallyconductive material associated therewith. A second substantiallytransparent substrate is spaced apart from the first substrate to definea cavity. The second substrate includes a second electrically conductivematerial associated therewith. One or more substantially rigid discs aredisposed between the first and second substrates. The one or more discsare configured to maintain a cell spacing between the first and secondsubstrates. An electro-optic medium is disposed within the cavity and isvariably transmissive such that the electro-optic device is operablebetween a substantially clear state and a darkened state. Asubstantially transparent light emitting display is operably coupled tothe electro-optic device and operable between ON and OFF conditions. Theelectro-optic device is in the darkened state when the light emittingdisplay is emitting light in the ON condition.

These and other aspects, objects, and features of the present disclosurewill be understood and appreciated by those skilled in the art uponstudying the following specification, claims, and appended drawings. Itwill also be understood that features of each embodiment disclosedherein may be used in conjunction with, or as a replacement for,features of the other embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a front plan view of a an emissive display system according toone aspect of the disclosure;

FIG. 2A is a cross-sectional view of the emissive display system of FIG.1 taken at line IIA, in accordance with an aspect of the disclosure;

FIG. 2B is a cross-sectional view of an emissive display system, inaccordance with another aspect of the disclosure;

FIG. 2C is a cross-sectional view of an emissive display system, inaccordance with another aspect of the disclosure;

FIG. 3A is a cross-sectional view of an emissive display system, inaccordance with another aspect of the disclosure;

FIG. 3B is a cross-sectional view of an emissive display system, inaccordance with another aspect of the disclosure; and

FIG. 4 is an enlarged, cross-sectional view of an emissive displaysystem, in accordance with yet another aspect of the disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

The present illustrated embodiments reside primarily in combinations ofmethod steps and apparatus components related to an electro-opticdevice. Accordingly, the apparatus components and method steps have beenrepresented, where appropriate, by conventional symbols in the drawings,showing only those specific details that are pertinent to understandingthe embodiments of the present disclosure so as not to obscure thedisclosure with details that will be readily apparent to those ofordinary skill in the art having the benefit of the description herein.Further, like numerals in the description and drawings represent likeelements.

In this document, relational terms, such as first and second, top andbottom, and the like, are used solely to distinguish one entity oraction from another entity or action, without necessarily requiring orimplying any actual such relationship or order between such entities oractions. The terms “comprises,” “comprising,” or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus. An element proceeded by “comprises . . . a” does not, withoutmore constraints, preclude the existence of additional identicalelements in the process, method, article, or apparatus that comprisesthe element.

Referring to FIGS. 1-4, an emissive display system 100 is depictedincluding a substantially transparent light emitting display (e.g.,organic light emitting diode (OLED) display 102). The substantiallytransparent light emitting display may be the OLED display 102, a lightemitting diode, a liquid-crystal display, an electroluminescent panel, aplasma display panel or other emissive display device. The emissivedisplay system 100 is operable between a transparent window state inwhich the emissive display system 100 is substantially transparent, anda viewing panel state in which the emissive display system 100 displaysan active image much like a television set. The transparent OLED display102 can include a substantially dark (e.g., black) background to enhanceOLED display 102 operation (e.g., visibility of emitted light andassociated display image). According to at least one embodiment of theemissive display system 100, the transparent OLED display 102 can beused in conjunction with an electro-optic device 104 (e.g., anelectrochromic device) to provide the substantially dark background.Typically, the electro-optic device 104 changes transmission statesbetween a substantially clear state and a substantially dark or darkenedstate, as well as intermediate states thereto. The darkened state of theelectro-optic device 104 is defined relative to the transmissivity ofthe substantially clear state. Typical transmissivity of theelectro-optic device 104 in the substantially clear state is greaterthan about 50%, more desirably greater than about 55%, and mostdesirably above about 60%. Typical transmissivity of the electro-opticdevice 104 in the substantially darkened state is less than about 1%,more desirably less than about 0.1%, and most desirably less than about0.001%. The emissive display system 100 can be configured such that theelectro-optic device 104 is in the darkened state when the OLED display102 is in an ON condition and emitting light. In this way, theelectro-optic device 104 defines a substantially dark background toenhance the viewing of the OLED display 102. Conversely, theelectro-optic device 104 can be in the substantially clear state whenthe OLED display 102 is in an OFF condition, or not emitting light, sothat the emissive display system 100 defines a substantially transparentwindow. It is also contemplated that the OLED display 102 may be ON andemitting light while the electro-optic device 104 is in thesubstantially clear state.

Referring now to FIG. 1, the emissive display system 100 may include abezel 106 disposed around a perimeter of the emissive display system100. The bezel 106 may operate to conceal edges of the OLED display 102and the electro-optic device 104. The bezel 106 may also house and/orconceal electronics and mounting hardware used in the operation of theemissive display system 100. The bezel 106 extends over the OLED display102 and electro-optic device 104 to define a viewing pane 110 disposedcentrally on the emissive display system 100. When emissive displaysystem 100 is in the transparent window state, with the OLED display 102in the off condition and the electro-optic device 104 in thesubstantially clear state, a viewer is able to look through the viewingpane 110, including the OLED display 102 and the electro-optic device104, to observe objects behind the emissive display system 100. Thus,when emissive display system 100 is in the transparent window state itmay function as a window of a house, office, automobile, airplane, orother vehicles and structures. When the emissive display system 100 isin the viewing panel state, with the OLED display 102 in the ONcondition and the electro-optic device 104 in the darkened state, theviewer observes light emitted from the OLED display 102 in the form of adisplay image disposed within the viewing pane 110.

FIG. 2A depicts an enlarged cross sectional view of the emissive displaysystem 100 of FIG. 1, without the bezel 106, to reveal greater detail.In the embodiment of FIG. 2A, the electro-optic device 104 comprises afirst substrate 120 having a front or first surface 122 and a secondsurface 124. A first conductive electrode portion 126 and a secondconductive electrode portion 128 applied to the second surface 124cooperate to define a first electrically conductive layer 129. The firstand second conductive electrode portions 126, 128 are substantiallyelectrically insulated from one another via a first isolation area 130.

With further reference to FIG. 2A, the first isolation area 130cooperates with a portion of a primary seal 132 to define the secondconductive electrode portion 128 and a second spectral filter portion134, each substantially electrically insulated from the first conductiveelectrode portion 126 and a first spectral filter portion 136. Thisconfiguration allows for placement of an electrically conductivematerial (e.g., a first conductive epoxy 138) adjacent to the primaryseal 132 and along the first substrate 120. A first electrical clip 140is in contact with the electrically conductive material 138 and isfurther in electrical communication with a third conductive electrodeportion 142, the second conductive electrode portion 128, and anelectro-optic medium 144 disposed within a cavity as further describedbelow. The material, or composition of materials, forming the thirdconductive electrode portion 142, the first electrical clip 140 and theelectrically conductive material 138 are chosen to promote durableelectrical communication between the clip 140 and the materials leadingto the electro-optic medium 144.

Referring again to FIG. 2A, the electro-optic device 104 is furtherincludes a second substrate 146 having a third surface 148 and a rear orfourth surface 150. It should be noted that the first substrate 120 maybe larger than the second substrate 146 to create an offset along atleast a portion of the perimeter of the emissive display system 100 (orvice versa). Additionally or alternatively, one of the first and secondsubstrates 120, 146 may have an approximately 26 inch to about 70 inchdiagonal, an approximately 12.7 inch to about 34.3 inch height, and anapproximately 22.7 inch to about 61 inch width, or a combinationthereof. In one embodiment, at least one of the first substrate and thesecond substrates 120, 146 can include a body portion having anapproximately 60 inch diagonal, an approximately 52 inch width, and anapproximately 29 inch height. The third conductive electrode portion 142and a fourth conductive electrode portion 152 are shown proximate thethird surface 148 substantially electrically insulated via a secondisolation area 154. The third and fourth conductive electrode portions142, 152 cooperate to define a second electrically conductive layer 153.

Referring again to FIG. 2A, the second isolation area 154 cooperateswith a portion of the primary seal 132 to define the fourth conductiveelectrode portion 152 that is substantially electrically insulated fromthe third conductive electrode portion 142. This configuration allowsfor placement of an electrically conductive material (e.g., a secondconductive epoxy 158) adjacent to the primary seal 132. A secondelectrical clip 160 is in electrical communication with the firstspectral filter portion 136, the first conductive electrode portion 126and the electro-optic medium 144 disposed within a cavity as furtherdescribed below. Preferably, the material, or composition of materials,forming the first conductive electrode portion 126, the secondelectrical clip 160, the first spectral filter portion 136 and theelectrically conductive material 158 are chosen to promote durableelectrical communication between the second electrical clip 160 and thematerials leading to the electro-optic medium 144.

Still referring to FIG. 2A, the electrically conductive material 138,158 is applied to outer edge portions 164, 166 of the electro-opticdevice 104, outboard from the primary seal 132, thereby electricallyconnecting the first and second electrically conductive layers 129, 153.By way of example and not limitation, the electrically conductivematerial 138, 158 may be a conductive solder, a conductive epoxy (e.g.,silver epoxy), a wire or other material capable of electrical signaltransfer. In some embodiments, the first substrate 120 may include atleast one electrical clip similar to the first and second electricalclips 140, 160 of the second substrate 146. In such an embodiment, thefirst and second conductive materials 138, 158 would no longerelectrically connect the first and second electrically conductive layers129, 153, thereby eliminating the need for the first and secondisolation areas 130, 154.

Still referring to FIG. 2A, the electrically conductive material 138,158 may be applied along outboard edges 168, 170 of the first substrate120 in a direction toward the first surface 122 so as to electricallyconnect a third electrically conductive layer 172 with the first andsecond electrical clips 140, 160. The third electrically conductivelayer 172 is disposed on the first surface 122 of the first substrate120, such that the first substrate 120 is a dual coated substrate havingelectrically conductive layers 129, 172 deposed on first and secondsurfaces 122, 124. As shown in FIG. 2A, the substantially transparentOLED display 102 is coupled to and receives power from the thirdelectrically conductive layer 172, such that the OLED display 102 isoperably coupled to the electro-optic device 104. Typically, traditionalOLED displays include both a glass substrate on which to lay anOLED/electrode layer and a cover glass portion protecting the OLEDdisplay 102 from oxygen. By utilizing the first surface 122 of the firstsubstrate 120 as a shared carrier for both the third electricallyconductive layer 172 and the OLED display 102, weight savings as well asdecreased manufacturing and material costs are achieved compared to themanufacture and assembly of separate components. It should be understoodthat the third electrically conductive layer 172 and the OLED display102 may alternatively or additionally be added to the fourth surface150, such that the second substrate 146 is also configurable as a dualcoated substrate. In such an embodiment, the electrically conductivematerial and/or the first and second electrical clips 140, 160 contactthe third electrically conductive layer 172 on the fourth surface 150 ina manner as described above with reference to the first substrate 120.

In an alternative embodiment, the OLED display 102 may instead bedisposed adjacent to the first surface 122 of the first substrate 120with the third electrically conductive layer 172 located on top of theOLED display 102 against a cover glass. The conductive material may beapplied along the OLED display 102 in a similar manner to that of theoutboard edges 168, 170 of the first substrate 120 to reach the thirdelectrically conductive layer 172. Such an embodiment may beadvantageous depending on the direction of the emission of light i.e.,whether the OLED display 102 is a top or bottom emission display device.

Still referring to FIG. 2A, in certain aspects of the emissive displaysystem 100, a perimeter material 174 is disposed on one or more edges ofthe first and second substrates 120, 146, the OLED display 102, theconductive material, and/or electrical clips 140, 160. The perimetermaterial 174, when present in the emissive display system 100, isselected to provide visible edge surfaces along the substrates that arevisually appealing while also providing adhesion between the edges ofthe electro-optic device 104 and the OLED display 102. In embodimentsincorporating a bezel such as the bezel 106 (FIG. 1), the perimetermaterial 174 may be omitted in assembly because the one or more edges ofthe first and second substrates 120, 146 would be concealed from theviewer by the bezel 106.

Still referring to FIG. 2A, the primary seal 132 traverses anapproximate perimeter of and is configured to cooperate with the firstand second substrates 120, 146 to define a substantially hermetic cavity176 disposed between the first and second substrate 120, 146. It shouldbe understood that the primary seal 132 may be applied to the first orsecond substrates 120, 146 by means commonly used in the liquid crystaldisplay (LCD) industry, such as by silk-screening or dispensing. Theelectro-optic medium 144 is disposed within the cavity 176, as shown inFIG. 2A. The primary seal 132, may include a plug that is used tofinally seal the cavity 176 after the cavity 176 is substantially filledwith the electro-optic medium 144. As shown, the cavity 176 includesboth a perimeter portion 178 and a central portion 180. The perimeterportion 178 is located proximate to the primary seal 132 in assembly.The first spectral filter portion 136 extends inboard from the primaryseal 132 into the perimeter portion 178 of the cavity 176 sufficientlyfar enough to generally conceal the primary seal 132 from the viewer.The central portion 180 of the cavity 176 shares approximately the samefoot print as the viewing pane 110 defined by the bezel 106 as describedin FIG. 1.

According to at least one embodiment, the electro-optic medium 144 is anelectrochromic medium. The electrochromic medium can comprise at leastone solvent, at least one anodic material, and at least one cathodicmaterial. Typically, both of the anodic and cathodic materials areelectroactive and at least one of them is electrochromic. The term“electroactive” can be a material that undergoes a modification in itsoxidation state upon exposure to a particular electrical potentialdifference, and/or the term “electrochromic” can be a material thatexhibits a change in its extinction coefficient at one or morewavelengths upon exposure to a particular electrical potentialdifference, according to one or more embodiments.

The electrochromic medium can be one of the following categories:

(I) Single-layer, single-phase—The electrochromic medium may comprise asingle-layer of material which may include small non-homogenous regions,and include solution-phase devices where a material may be contained insolution in an ionically conducting electrolyte which remains insolution in the electrolyte when electrochemically oxidized or reduced.Solution-phase electroactive materials may be contained in thecontinuous solution-phase of a gel medium in accordance with theteachings of U.S. Pat. No. 5,928,572 entitled “Electrochromic Layer AndDevices Comprising Same,” and International Patent Application SerialNo. PCT/US98/05570 entitled “Electrochromic Polymeric Solid Films,Manufacturing Electrochromic Devices Using Such Solid Films, AndProcesses For Making Such Solid Films And Devices,” both of which arehereby incorporated herein by reference in their entirety.

More than one anodic and cathodic material can be combined to give apre-selected color as described in U.S. Pat. No. 5,998,617 entitled“Electrochromic Compounds,” U.S. Pat. No. 6,020,987 entitled“Electrochromic Medium Capable Of Producing A Pre-selected Color,” U.S.Pat. No. 6,037,471 entitled “Electrochromic Compounds,” and U.S. Pat.No. 6,141,137 entitled “Electrochromic Media For Producing APre-selected Color,” all of which are hereby incorporated herein byreference in their entirety including all references incorporated and/orcited therein.

The anodic and cathodic materials may also be combined or linked by abridging unit as described in U.S. Pat. No. 6,241,916 entitled“Electrochromic System” and/or U.S. Patent Publication No. 2002/0015214A1 entitled “Electrochromic Device,” which are hereby incorporatedherein by reference in their entirety including all referencesincorporated and/or cited therein. The electrochromic materials may alsoinclude near-infrared (NIR) absorbing compounds as described in U.S.Pat. No. 6,193,912 entitled “Near Infrared-Absorbing ElectrochromicCompounds And Devices Comprising Same,” which is hereby incorporatedherein by reference in its entirety including all referencesincorporated and/or cited therein.

It is also possible to link anodic materials or cathodic materials bysimilar methods. The concepts described in these patents can further becombined to yield a variety of electroactive materials that are linkedor coupled, including linking of a redox buffer, such as linking of acolor-stabilizing moiety, to an anodic and/or cathodic material.

The anodic and cathodic electrochromic materials can also includecoupled materials as described in U.S. Pat. No. 6,249,369 entitled“Coupled Electrochromic Compounds With Photostable Dication OxidationStates,” which is hereby incorporated herein by reference in itsentirety including all references incorporated and/or cited therein.

The concentration of the electrochromic materials can be selected astaught in U.S. Pat. No. 6,137,620 entitled “Electrochromic Media WithConcentration Enhanced Stability, Process For The Preparation Thereofand Use In Electrochromic Devices,” which is hereby incorporated hereinby reference in its entirety including all references incorporatedand/or cited therein.

Additionally, a single-layer, single-phase medium may include a mediumwhere the anodic and cathodic materials are incorporated into a polymermatrix as is described in International Patent Application Serial No.PCT/EP98/03862 entitled “Electrochromic Polymer System,” andInternational Patent Application Serial No. PCT/US98/05570 entitled“Electrochromic Polymeric Solid Films, Manufacturing ElectrochromicDevices Using Such Solid Films, And Processes For Making Such SolidFilms And Devices,” which is hereby incorporated herein by reference inits entirety including all references incorporated and/or cited therein.

(II) Multi-layer—The electrochromic medium may also be prepared inlayers and include a material attached directly to an electricallyconducting electrode or confined in close proximity thereto whichremains attached or confined when electrochemically oxidized or reduced.

(III) Multi-phase—The electrochromic medium may further be preparedusing multiple phases where one or more materials in the mediumundergoes a change in phase during the operation of the device. Forexample a material contained in solution in the ionically conductingelectrolyte forms a layer on the electrically conducting electrode whenelectrochemically oxidized or reduced.

Referring again to the embodiment of FIG. 2A, one or more beads 190 maybe disposed in the cavity 176 to maintain an approximately equal cellspacing between the first substrate 120 and the second substrate 146within the electro-optic device 104. In the assembly and manufacture ofelectro-optics devices, beads, such as beads 190, may be disposed in thecentral portion 180 of the cavity 176 by affixing the beads 190 toeither the second or third surfaces 124, 148 of either the first orsecond substrates 120, 146. The beads 190 may be positioned inboard ofthe primary seal 132 to temporarily maintain proper cell spacing of thecavity 176 during the manufacturing process prior to and during curingof the primary seal 132. In assembly, and as shown in FIG. 2A, the beads190 about the second and third surfaces 124, 148 act to physicallyseparate the first and second substrates 120, 146 thereby setting thecell spacing of the cavity 176 as the largest dimension of the beads190. The beads 190 are particularly useful in the manufacture ofelectro-optic devices having large or thin substrates, as the beads 190help prevent distortion and double image during device manufacture giventhe structural rigidity of the beads. This rigidity maintains a uniformcell spacing between the substrates 120, 146 until gelation of theelectro-optic medium 144 occurs. The use of beads 190 is alsoadvantageous from a cost savings standpoint, as the beads 190 are a costeffective way to maintain cell spacing without the use of highlyspecialized equipment.

The cavity 176 of the electro-optic device 104 can be configured to havean approximately 0.5 millimeter cell spacing, or spacing between thefirst substrate 120 and the second substrate 146, according to at leastone embodiment. In such an embodiment, the beads 190 are configured tobe approximately 0.5 millimeters in height and/or diameter. Generally,the beads 190 are used to maintain cell spacing for a relatively shortperiod of time during the manufacture of an electro-optic device. Thus,the beads 190 should have a diameter or largest dimension equal to orslightly greater than a desired cell spacing for the electro-opticdevice 104. Selection of properly sized beads can be accomplished bysieving through successive screens to obtain a desired size. Thediameter of the beads 190 may be about 100 microns to about 2000microns, and more desirably, between about 250 microns to about 1000microns. By way of explanation and not limitation, the beads 190 may bein a column or pillar orientation as shown in FIG. 2A, or the beads 190may also have a substantially round or spherical orientation. It will beunderstood by one having ordinary skill in the art that the beads 190described throughout this disclosure can be replaced by any form ofspacing member having a configuration that is not substantiallyspherical, but may be substantially cubic, conical, cylindrical,rectangular, pyramid shaped, randomly formed by a printing technique, orany other configuration appropriate to maintain the cell spacing.

The beads 190 can be approximately uniform in color. In someembodiments, the beads 190 may be substantially dark and consistent withthe color of the electro-optic device 104 in the darkened state. Thebeads 190 may also be substantially opaque, such that when theelectro-optic device 104 is in the darkened state, the beads 190 do notresult in points of high transmissivity of light. Thus, when the beads190 are opaque, the electro-optic device 104 maintains a substantiallyuniform level of transmissivity of light while in the darkened state.

The beads 190 can include glasses, polymers, ceramics, organics,inorganics, salts and other suitable non-conductive materials, orcombinations thereof. For example, the beads 190 may be substantiallycomposed of a polymethyl methacrylate material. Additionally, the beads190 can be colored, clear, or opaque and may further be configured tovary in transmissivity to control the amount or wavelength of light thatpropagates through the beads 190. For example, in embodiments where thebeads 190 are composed of glass, the glass may be basalt, such thatoptical light is occluded from passing through the beads 190. Inembodiments where the beads 190 include clear plastics or light coloredceramics, the beads 190 may be dyed a dark color to occlude light andprovide a substantially uniform color for the electro-optic device 104in the darkened state.

Additionally, the beads 190 may comprise a variety of otherelectromagnetic properties. For example, the beads 190 may be magnetic,paramagnetic, ferromagnetic, diamagnetic, electrically charged, orotherwise responsive to the generation and manipulation ofelectromagnetic fields for movement within the cavity 176, as furtherdescribed below.

Typically, the beads 190 are loaded into a “salt shaker” type dispenser.When applying the beads 190 to a substrate, either the first or secondsubstrate 120, 146 is laid flat with the electrode coated side facingupward. The beads 190 are then randomly distributed onto the second orthird surfaces 124, 148 using the salt shaker dispenser to aconcentration of about 5 to 10 beads per square centimeter.Additionally, the beads 190 can be printed onto a surface of one of thesubstrates, using a three-dimensional printing technique or other likeadditive manufacturing process.

Still referring to FIG. 2A, in some embodiments, the beads 190 mayremain in the central portion 180 of the cavity 176 after curing of theprimary seal 132 and during gelation of the electro-optic medium 144. Insuch embodiments, dark beads 190 having substantially the same color asthe electro-optic device 104 in the darkened state are desired.Typically, dark colored beads 190 positioned in the central portion 180of the cavity 176 are visible in the viewing pane 110 by the viewer;however, typical viewing distances for large emissive displays andwindows are of such a distance that dark colored beads of apredetermined size are substantially undetected under typical viewingconditions. For example, with the emissive display system 100 in thetransparent window state, a viewer would generally not detect thepresence of the dark beads 190 due to the small bead size and theviewer's distance to the viewing pane 110. In this state, the viewingpane 110 appears as a substantially transparent window. Similarly, theopacity and the dark color of the beads 190 would occlude light frompassing through the electro-optic device 104, such that when theelectro-optic device 104 is in the darkened state, it has asubstantially uniform light transmissivity. Thus, the beads 190generally blend with the electro-optic device 104, such that the viewerwould not observe high points of transmissivity or “pinpricks” of lightpassing through the emissive display system 100. With the beads 190 notreadily visible in either the transparent window state or the viewingpanel state, the beads 190 are thus substantially concealed from theviewer in both the substantially clear and darkened states of theelectro-optic device 104.

Referring now to FIG. 2B, another embodiment of an emissive displaysystem 100A is shown having one or more beads 190 disposed on their sidein the perimeter portion 178 of the cavity 176. Once the primary seal132 is cured, the beads 190 of emissive display system 100A can be movedto the perimeter portion 178 of the cavity 176 at or proximate to theprimary seal 132. The beads 190 may be movable to the perimeter portion178 of the cavity 176, such that the beads 190 are removed or dispersedoutside of the viewing pane 110, thus concealing the beads 190 from theviewer. For example, once moved to the perimeter portion 178, the beads190 may come to rest under the first and second spectral filter portions136, 134 and be concealed from the viewer. In another example, the beads190 may be moved under the bezel 106 (FIG. 1), such that the viewer doesnot see the beads 190 in assembly. In embodiments where the beads 190are concealed under the bezel 106, the first and second spectral filterportions 136, 134 may be omitted in assembly.

Referring again to FIG. 2B, according to one embodiment, the beads 190may be moved magnetically from the central portion 180 of the cavity 176to the perimeter portion 178 of the cavity 176. In such an embodiment,the beads 190 may be composed of a material responsive toelectromagnetic fields, such as a paramagnetic polymer or aferromagnetic polymer, and positioned in the central portion 180 of thecavity 176. After the seal 132 is cured, an electromagnetic field may begenerated and manipulated in order to generate a magnetic force on thebeads 190. The magnetic force may be used to attract or repel the beads190 towards the perimeter portion 178 of the cavity 176, such that theyare substantially concealed (e.g., under the spectral filter portions136, 134 or bezel 106) from the viewer.

With further reference to FIG. 2B, according to another embodiment, thebeads 190 may be gravitationally moved from the central portion 180 ofthe cavity 176 to the perimeter portion 178. After curing of the primaryseal 132 and the filling of the cavity 176 with the electro-optic medium144, the electro-optic device 104 may be positioned in a verticalorientation. The vertical orientation of the electro-optic device 104causes the yet ungelled electro-optic medium 144 to generate anoutwardly oriented hydrostatic force within the electro-optic device104. The outwardly oriented hydrostatic force minutely increases thecell spacing in the cavity 176 allowing the beads 190 to gravitationallydescend to the perimeter portion 178 of the cavity 176 proximate to theprimary seal 132. In an alternative embodiment, prior to filling thecavity 176 with electro-optic medium 144, but after curing of theprimary seal 132, a burst of air may be introduced to the cavity 176.The burst of air generates an outwardly oriented force, similarly tothat of the hydrostatic force, allowing the beads 190 to gravitationallydescend towards the perimeter portion 178 of the cavity 176. In thisembodiment, the beads 190 may then be removed from the cavity 176.

Additionally, the introduction of the electro-optic medium 144 to thecavity 176 may itself aid in the movement of the beads 190. As theelectro-optic medium 144 moves through the cavity 176, it may pillow thesubstrates 120, 146, or slightly increase the cell spacing, allowing thebeads 190 to be moved to the perimeter portion 178. The remaining beads190 in the cavity 176 may then be moved using one of the methodsoutlined above.

Referring now to another embodiment of the emissive display system 100Bshown in FIG. 2C, the usage of beads 190 in the electro-optic device 104may be optimized by placing the beads 190 in predetermined locations.The predetermined locations may correspond to a grid pattern, a gradientpattern, circular pattern, striped pattern or another arrangement basedon localized support needs between the first and second substrates 120,146 during the manufacturing process. Rigidity of the electro-opticdevice 104 may also be considered in determining the location of thebeads 190. The beads 190 may be held in place in predetermined locationswith the use of a retaining medium 192. The retaining medium 192 iscontemplated to be a semiliquid or a partially solidified material. Theretaining medium 192 is contemplated to be a crosslinked or highviscosity polymer with adhesive properties. In some embodiments, theretaining medium 192 may include one or more of the constituents of theelectro-optic medium 144 (e.g., propylene carbonate). Embodimentsutilizing a constituent of the electro-optic medium 144 are advantageousas they avoid poisoning or tainting of the electro-optic medium 144 withforeign substances while simultaneously holding the beads 190 in place.In one embodiment, a plurality of basalt glass beads 190 are dispensedin predetermined grid pattern on the third surface 148 of the secondsubstrate 146 using propylene carbonate as the retaining medium 192.Additionally, once the cavity 176 has been filled with electro-opticmedium 144, but prior to gelation, the retaining medium 192 may dissolveinto the electro-optic medium 144, thereby freeing the beads 190 to bemoved from the central portion 180 of the cavity 176 to the perimeterportion 178 using one of the moving methods outlined above.

Referring now to FIG. 3A, in one embodiment of the emissive displaysystem 100C, spacer members, such as pre-formed polymer matrix discs200, can be used to maintain an approximate cell spacing between thefirst and second substrates 120, 146. The polymer matrix discs 200 maybe sufficiently crosslinked, thereby providing the rigidity to maintainthe cell spacing between the first and second substrates 120, 146 duringmanufacturing. The pre-formed polymer matrix discs 200 are generallyformed of crosslinked polymer chains. The polymer chains containfunctional groups that will allow for additional crosslinking, likehydroxyls, amines, isocyanates, isothiocyanates, and/or glycidyls. Thepolymer chains of the polymer matrix maybe from the following classes ofpolymers: polyacrylate, polymethacrylates, polyethers, polyesters,polycarbonates, polyvinylesters, polyurethanes, polysiloxanes,polysilanes, polyacrylonitriles, polystyrenes, polymethacrylonitriles,polyamides, polyimides, polyvinylidenehalides, and co-polymer andcombinations of thereof. The polymer chains of the pre-formed polymermatrix discs 200 may be crosslinked by reaction with a compound having afunctional group selected from the group consisting of aromatic andaliphatic hydroxyl; aromatic and aliphatic amines; aromatic andaliphatic isocyanato; aliphatic and aromatic isothiocyanato and aromaticand aliphatic glycidyls. Further examples of polymer matrix materialscan be found in U.S. Pat. Nos. 6,635,194 and 5,940,201, which are herebyincorporated by reference in their entirety including all referencesincorporated and/or cited therein. The pre-formed polymer discs 200 mayhave a diameter ranging from about 0.5 to about 1.5 centimeters and moredesirably about 1 centimeter. The pre-formed polymer matrix discs 200may also include a height ranging from about 0.25 millimeters to about 1millimeter, and more desirably about 0.5 millimeters. The polymer matrixdiscs 200 are substantially transparent, and thus, substantiallyundetectable in assembly. The pre-formed polymer discs 200 may bedistributed on to the second or third surfaces 124, 148 in a similarmanner to that described above with reference to the beads 190. Forexample, the discs 200 may be randomly distributed or may be placed in apredetermined pattern based on spacing and rigidity needs of theelectro-optic device 104.

With further reference to FIG. 3A, in one embodiment, the polymer matricdiscs 200 are formed without an electroactive material. During assembly,an electroactive material from the electro-optic medium 144 can bediffused into the polymer matrix discs 200. The presence ofelectroactive material (e.g., electrochromic material) within thepolymer matrix discs 200 permits the polymer matrix discs 200 to bevariably transmissive, in a manner similar to the electro-optic medium144. Additionally, the polymer matrix discs 200 may be formed with theelectroactive material (e.g., electrochromic material) pre-impregnatedinto the polymer matrix discs 200, with additional electroactivematerial diffusing inwardly from the electro-optic medium 144 prior togelation of the electro-optic medium 144. The polymer matrix discs 200are substantially concealed from the viewer in both the substantiallyclear and darkened states of the electro-optic device 104 due to thevariable transmissivity imparted by the electroactive material diffusedor impregnated therein.

Referring now to FIG. 3B, in at least one embodiment of the emissivedisplay system 100D, the spacing members may be in the form of geldeposits 220 which act to maintain the appropriate cell spacing of thecavity 176 between the first and second substrates 120, 146. The geldeposits 220 may include a crosslinked polymer matrix, a free-standinggel or a substantially non-weeping gel. In an alternative embodiment,the gel deposit 220 may comprise non-cross linked polymers in order tospeed dissolution of the deposit 220 into the electro-optic medium 144.It is contemplated that the gel deposits 220 comprise a semi-solubilizedplastic mixture configured to maintain cell spacing and dissolve uponassociation with a solvent from the electro-optic medium 144.

Referring again to FIG. 3B, the gel deposits 220 may be a plasticmixture including a polymeric component selected from the groupconsisting of a polymethyl methacrylate component, a poly(propylenecarbonate) component and combinations and co-polymers thereof.Similarly, the gel deposits 220 may include a polymeric componentcomprising a backbone selected from the group consisting of polyamides,polyimides, polycarbonates, polyesters, polyethers, polymethacrylates,polyacrylates, polysilanes, polysiloxanes, polyvinylacetates,polymethacrylonitriles, polyacrylonitriles, polyvinylphenols,polyvinylalcohols, polyvinylidenehalides, and co-polymers andcombinations thereof. In assembly, the gel deposits 220 are configuredto remain substantially rigid after filling the cavity 176 with theelectro-optic medium 144 to provide support for electro-optic device104. In another embodiment, the gel deposits 220 are configured tosubstantially dissolve into the electro-optic medium 144 prior tocrosslinking of the electro-optic medium 144. In such an embodiment, thegel deposits 220 function as a “sacrificial spacing member” to maintainthe cell spacing of the cavity 176 and then substantially dissolve intothe electro-optic medium 144 upon association with the same.

Depicted in FIG. 4 is another embodiment of the primary seal 132 of anemissive display system 100E, shown in an enlarged, cross-sectionalformat to provide additional detail associated with salient features ofthe various, exemplary embodiments of this disclosure. In thisembodiment, the primary seal 132 includes a gasket 230 disposed betweena first epoxy layer 232 and a second epoxy layer 234. In the depictedembodiment, the gasket 230 may extend through the width of the primaryseal 132 to the edge of the first and second substrates 120, 146 andmake contact with the conductive material (e.g., conductive epoxy 138,158). In other embodiments, the gasket 230 may terminate within theprimary seal 132 (i.e., the first or second epoxy layers 232, 234 mayenvelop an outboard and/or inboard edge of the gasket 230). The gasket230 and primary seal 132 are configured to be substantially concealedwhen used in embodiments where the emissive display system 100E includesfirst and second spectral filter portions 136, 134 or a bezel, such asbezel 106 shown in FIG. 1.

Referring again to FIG. 4, the gasket 230 extends around the first andsecond substrates 120, 146 within the primary seal 132. The gasket 230may be a unitary structure, as depicted, or be composed of severalpieces. In embodiments where the gasket 230 is composed of multiplepieces, the pieces may be joined via butt joints, miter joints, splicejoints, or other known methods of joining gaskets. The gasket 230 has athickness which may range from about 100 microns to about 2000 microns,and more desirably range from about 250 microns to about 1000 microns.The gasket 230 is composed of a material which is both an electricalinsulator and promotes a hermetic environment within the cavity 176(i.e., prevents the diffusion of oxygen and moisture vapor from anexternal environment to the cavity 176). Suitable materials for thegasket 230 may include glasses, plastics, ceramics or combinationsthereof. According to at least one embodiment, one or more borosilicateglass strips can be used to form the gasket 230. In such an embodiment,the cavity 176 would be expected to have an increased hermaticity due tothe replacement of an epoxy with a glass gasket 230, as furtherdescribed below. In some embodiments, the gasket 230 may be configuredto function as an electrical bus extending around a perimeter of theelectro-optic device 104. In such embodiments, the gasket 230 is coatedwith an electrically conductive metal (e.g., silver, copper, gold),polymer, or combination thereof. The gasket 230, when functioning as anelectrical bus, may be electrically connected to the first or secondelectrically conductive layers 129, 153 by modifying one or both of thefirst and second electrical clips 140, 160 to make contact with thegasket 230. Additionally or alternatively, a wire may be disposed in thefirst or second epoxy layers 232, 234 to create an electrical connectionbetween the gasket 230 and the first or second electrically conductivelayers 129, 153. It should be understood that the methods of creatingthe electrical connection between the gasket 230 and the conductivelayers 129, 153 outlined above are exemplary in nature and are notintended to be limiting.

With further reference to FIG. 4, disposed within the first and secondepoxy layers 232, 234 are one or more seal spacer beads 236. The sealspacer beads 236 are used to help define the cell spacing of the cavity176 in the electro-optic device 104. Traditional epoxy seals typicallyhave a higher coefficient of thermal expansion as compared to sealshaving a glass spacer media included within the epoxy. In seals thatinclude a high temperature curing step followed by a cool down phase,the difference in coefficients of thermal expansion between the epoxyand the spacer media can lead to high stresses in the epoxy whichresults in delamination of the epoxy from larger (i.e., greater thanabout 250 microns) spacing media. However, the introduction of thegasket 230 permits the use of spacing beads 236 of a smaller size i.e.,less than about 250 microns while still producing electro-optic devices104 with a sufficiently large cell spacing. In this embodiment, thegasket 230 acts as a filler between the first and second substrates 120,146, such that spacing beads 236 of a smaller diameter, which do notsuffer from the same delamination issues outlined above, may be used inthe epoxy.

Still referring to FIG. 4, the seal spacing beads 236 may be composed ofa polymer, a glass, a ceramic, or other suitable hermetic andnon-conductive media. Alternatively, in embodiments where the gasket 230is functioning as an electrical bus, the seal spacing beads 236 may becoated in or include an electrically conductive metal so as to providean electrical connection between the electrical clips 140, 160, thegasket 230, and the first or second electrically conductive layers 129,153 using the spacing beads 236. The spacer beads 236 may range indiameter from about 1 micron to about 250 microns, and more desirablyfrom about 50 microns to about 100 microns. In assembly, the sealspacing beads 236 are configured to define the spacing between thelaminated first and second substrates 120, 146. The spacing beads 236may be placed into the first and second epoxy layers 232, 234 (e.g.,before or after the seal material is dispensed within the emissivedisplay system 100E and cured) or applied to the first or secondsubstrates 120, 146 prior to joining of the substrates.

Examples are described in U.S. Pat. Nos. 6,700,692, 7,372,611, and8,169,684, and U.S. patent application Ser. Nos. 12/496,620, 12/774,721,13/395,069 and 13/470,147, all of which are hereby incorporated hereinby reference in their entirety.

The present disclosure may be used with a display system such as thatdescribed in U.S. Pat. Nos. 8,201,800; 8,210,695; U.S. patentapplication Ser. Nos. 13/600,496; 13/527,375; 13/431,657; 13/402,701;12/187,019, and U.S. Provisional Patent Application Nos. 61/709,716;61/707,676; and 61/704,869, which are hereby incorporated herein byreference in their entirety. Further, the present disclosure may be usedwith a rearview packaging assembly such as that described in U.S. Pat.No. 8,264,761; U.S. patent application Ser. Nos. 13/567,363; 13/405,697;13/402,701; and 13/171,950, and U.S. Provisional Patent Application Nos.61/707,625; and 61/590,259, which are hereby incorporated herein byreference in their entirety. Additionally, it is contemplated that thepresent disclosure can include another bezel such as that described inU.S. Pat. Nos. 8,201,800; 8,210,695; and U.S. patent application Ser.No. 13/271,745, which is hereby incorporated herein by reference in itsentirety.

Modifications of the disclosure will occur to those skilled in the artand to those who make or use the disclosure. Therefore, it is understoodthat the embodiments shown in the drawings and described above aremerely for illustrative purposes and not intended to limit the scope ofthe disclosure, which is defined by the following claims as interpretedaccording to the principles of patent law, including the doctrine ofequivalents.

It will be understood by one having ordinary skill in the art thatconstruction of the described disclosure and other components is notlimited to any specific material. Other exemplary embodiments of thedisclosure disclosed herein may be formed from a wide variety ofmaterials, unless described otherwise herein.

For purposes of this disclosure, the term “coupled” (in all of itsforms, couple, coupling, coupled, etc.) generally means the joining oftwo components (electrical or mechanical) directly or indirectly to oneanother. Such joining may be stationary in nature or movable in nature.Such joining may be achieved with the two components (electrical ormechanical) and any additional intermediate members being integrallyformed as a single unitary body with one another or with the twocomponents. Such joining may be permanent in nature or may be removableor releasable in nature unless otherwise stated.

It is also important to note that the construction and arrangement ofthe elements of the disclosure as shown in the exemplary embodiments isillustrative only. Although only a few embodiments of the presentinnovations have been described in detail in this disclosure, thoseskilled in the art who review this disclosure will readily appreciatethat many modifications are possible (e.g., variations in sizes,dimensions, structures, shapes and proportions of the various elements,values of parameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter recited. For example,elements shown as integrally formed may be constructed of multiple partsor elements shown as multiple parts may be integrally formed, theoperation of the interfaces may be reversed or otherwise varied, thelength or width of the structures and/or members or connector or otherelements of the system may be varied, the nature or numeral ofadjustment positions provided between the elements may be varied. Itshould be noted that the elements and/or assemblies of the system may beconstructed from any of a wide variety of materials that providesufficient strength or durability, in any of a wide variety of colors,textures, and combinations. Accordingly, all such modifications areintended to be included within the scope of the present innovations.Other substitutions, modifications, changes, and omissions may be madein the design, operating conditions, and arrangement of the desired andother exemplary embodiments without departing from the spirit of thepresent innovations.

It will be understood that any described processes or steps withindescribed processes may be combined with other disclosed processes orsteps to form structures within the scope of the present disclosure. Theexemplary structures and processes disclosed herein are for illustrativepurposes and are not to be construed as limiting.

It is also to be understood that variations and modifications can bemade on the aforementioned structures and methods without departing fromthe concepts of the present disclosure, and further it is to beunderstood that such concepts are intended to be covered by thefollowing claims unless these claims by their language expressly stateotherwise.

What is claimed is:
 1. An emissive display system, comprising: an electro-optic device comprising: a first substantially transparent substrate having a first electrically conductive material associated therewith; a second substantially transparent substrate spaced apart from the first substrate to define a cavity and having a second electrically conductive material associated therewith; one or more spacing members positioned within the cavity, wherein the one or more spacing members comprise one or more polymer matrix discs configured to maintain a cell spacing between the first and second substrates, further wherein the one or more spacing members are variably transmissive between substantially clear and darkened states; an electro-optic medium disposed within the cavity, the electro-optic medium being variably transmissive such that the electro-optic device is operable between substantially clear and darkened states, the electro-optic medium comprising: at least one solvent; at least one anodic material; at least one cathodic material; and a substantially transparent light emitting display operably coupled to the electro-optic device, wherein the electro-optic device is in the darkened state when the light emitting display is emitting light.
 2. The emissive display system of claim 1, wherein the one or more spacing members are substantially transparent.
 3. The emissive display system of claim 2, wherein the electro-optic medium diffuses into the one or more spacing members upon association, such that the one or more spacing members are variably transmissive.
 4. The emissive display system of claim 3, wherein both of the at least one anodic and at least one cathodic materials are electroactive and at least one of the at least one anodic and at least one cathodic materials is electrochromic.
 5. The emissive display system of claim 1, wherein the one or more spacing members are isocyanate reaction products.
 6. The emissive display system of claim 1, wherein the one or more spacing members are substantially concealed in the electro-optic device when the electro-optic medium is in the darkened state.
 7. The emissive display system of claim 1, wherein the one or more spacing members have a diameter of approximately 1 centimeter and the cell spacing is approximately 0.5 millimeters.
 8. The emissive display system of claim 1, wherein the light emitting display is an organic light emitting diode display.
 9. An emissive display system, comprising: an electro-optic device comprising: a first substantially transparent substrate having a first electrically conductive material associated therewith; a second substantially transparent substrate spaced apart from the first substrate to define a cavity and having a second electrically conductive material associated therewith; one or more spacing members positioned within the cavity, wherein the one or more spacing members are configured to maintain a cell spacing between the first and second substrates, further wherein the spacing members are variably transmissive between substantially clear and darkened states; an electro-optic medium disposed within the cavity, the electro optic medium being variably transmissive such that the electro-optic device is operable between a substantially clear state and a darkened state; and a substantially transparent light emitting display operably coupled to the electro-optic device and configured to display a visible image by selectively emitting light, wherein the electro-optic device is in the darkened state when the light emitting display is emitting light.
 10. The emissive display system of claim 9, wherein the one or more spacing members are substantially transparent.
 11. The emissive display system of claim 10, wherein the one or more spacing members are comprised of a crosslinked polymer matrix.
 12. The emissive display system of claim 11, wherein the electro-optic medium includes at least one solvent, at least one anodic material, at least one electrochromic material, and at least one cathodic material.
 13. The emissive display system of claim 12, wherein the at least one electrochromic material is in solution with the solvent and is further interspersed in the crosslinked polymer matrix of the one or more spacing members.
 14. The emissive display system of claim 11, wherein the polymer matrix results from crosslinking polymer chains and further wherein the polymer chains are from the following classes of polymers: polyacrylate, polymethacrylates, polyethers, polyesters, polycarbonates, polyvinylesters, polyurethanes, polysiloxanes, polysilanes, polyacrylonitriles, polystyrenes, polymethacrylonitriles, polyamides, polyimides, polyvinylidenehalides, and co-polymer and combinations of thereof.
 15. The emissive display system of claim 14, wherein the polymer chains are cross-linked by reaction with a compound having a functional group selected from the group consisting of aromatic and aliphatic hydroxyl; aromatic and aliphatic isocyanate; aliphatic and aromatic isothiocyanato; aromatic and aliphatic glycidyls; aromatic and aliphatic amines.
 16. The emissive display system of claim 9, wherein the light emitting display is an organic light emitting diode display.
 17. An emissive display system, comprising: an electro-optic device comprising: a first substantially transparent substrate having a first electrically conductive material associated therewith; a second substantially transparent substrate spaced apart from the first substrate to define a cavity, the second substrate having a second electrically conductive material associated therewith; one or more substantially rigid discs disposed between the first and second substrates, wherein the one or more discs are configured to maintain a cell spacing between the first and second substrates, further wherein the one or more substantially rigid discs are variably transmissive between substantially clear and darkened states; an electro-optic medium disposed within the cavity, the electro-optic medium being variably transmissive such that the electro-optic device is operable between a substantially clear state and a darkened state; and a substantially transparent light emitting display operably coupled to the electro-optic device and operable between ON and OFF conditions, wherein the electro-optic device is in the darkened state when the light emitting display is emitting light in the ON condition.
 18. The emissive display system of claim 17, wherein the one or more discs are comprised of a crosslinked polymer matrix and are substantially transparent.
 19. The emissive display system of claim 18, wherein the electro-optic medium includes at least one electrochromic material in solution with a solvent, and further wherein the at least one electrochromic material is interspersed in the crosslinked polymer matrix of the one or more discs.
 20. The emissive display system of claim 17, wherein the light emitting display is an organic light emitting diode display. 